[GStreamer][WebRTC] Some tests hitting hashtable asserts

https://bugs.webkit.org/show_bug.cgi?id=261148

Reviewed by Xabier Rodriguez-Calvar.

Bail out from meta copy function if the transform type is not supported. The same check is done in
other implementations such as GstVideoMeta.

* Source/WebCore/platform/graphics/gstreamer/VideoFrameMetadataGStreamer.cpp:
(videoFrameMetadataGetInfo):

Canonical link: https://commits.webkit.org/267721@main

Source/WebCore/platform/graphics/gstreamer/VideoFrameMetadataGStreamer.cpp

@@ -86,10 +86,14 @@ const GstMetaInfo* videoFrameMetadataGetInfo()
                 auto* frameMeta = VIDEO_FRAME_METADATA_CAST(meta);
                 destroyVideoFrameMetadataPrivate(frameMeta->priv);
             },
-            [](GstBuffer* buffer, GstMeta* meta, GstBuffer*, GQuark type, gpointer) -> gboolean {
+            [](GstBuffer* buffer, GstMeta* meta, GstBuffer*, GQuark type, gpointer data) -> gboolean {
                 if (!GST_META_TRANSFORM_IS_COPY(type))
                     return FALSE;
 
+                auto transformCopy = reinterpret_cast<GstMetaTransformCopy*>(data);
+                if (!transformCopy->region)
+                    return FALSE;
+
                 auto* frameMeta = VIDEO_FRAME_METADATA_CAST(meta);
                 auto [buf, copyMeta] = ensureVideoFrameMetadata(buffer);
                 copyMeta->priv->videoSampleMetadata = frameMeta->priv->videoSampleMetadata;